2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
37 #include <linux/types.h>
38 #include <linux/major.h>
39 #include <linux/errno.h>
40 #include <linux/signal.h>
41 #include <linux/fcntl.h>
42 #include <linux/sched/signal.h>
43 #include <linux/interrupt.h>
44 #include <linux/tty.h>
45 #include <linux/ctype.h>
47 #include <linux/string.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/bitops.h>
51 #include <linux/file.h>
52 #include <linux/uaccess.h>
53 #include <linux/module.h>
54 #include <linux/timer.h>
55 #include <linux/tty_flip.h>
56 #include <linux/tty_driver.h>
57 #include <linux/serial.h>
58 #include <linux/kfifo.h>
59 #include <linux/skbuff.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/gsmmux.h>
67 module_param(debug, int, 0600);
69 /* Defaults: these are from the specification */
71 #define T1 10 /* 100mS */
72 #define T2 34 /* 333mS */
73 #define N2 3 /* Retry 3 times */
75 /* Use long timers for testing at low speed with debug on */
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
87 #define GSM_NET_TX_TIMEOUT (HZ*10)
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
93 * Created when net interface is initialized.
97 struct gsm_dlci *dlci;
101 * Each block of data we have queued to go out is in the form of
102 * a gsm_msg which holds everything we need in a link layer independent
107 struct list_head list;
108 u8 addr; /* DLCI address + flags */
109 u8 ctrl; /* Control byte + flags */
110 unsigned int len; /* Length of data block (can be zero) */
111 unsigned char *data; /* Points into buffer but not at the start */
112 unsigned char buffer[0];
116 * Each active data link has a gsm_dlci structure associated which ties
117 * the link layer to an optional tty (if the tty side is open). To avoid
118 * complexity right now these are only ever freed up when the mux is
121 * At the moment we don't free DLCI objects until the mux is torn down
122 * this avoid object life time issues but might be worth review later.
129 #define DLCI_CLOSED 0
130 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
131 #define DLCI_OPEN 2 /* SABM/UA complete */
132 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 #define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
138 #define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
139 spinlock_t lock; /* Protects the internal state */
140 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 /* Uplink tty if active */
143 struct tty_port port; /* The tty bound to this DLCI if there is one */
144 struct kfifo *fifo; /* Queue fifo for the DLCI */
145 struct kfifo _fifo; /* For new fifo API porting only */
146 int adaption; /* Adaption layer in use */
148 u32 modem_rx; /* Our incoming virtual modem lines */
149 u32 modem_tx; /* Our outgoing modem lines */
150 int dead; /* Refuse re-open */
152 int throttled; /* Private copy of throttle state */
153 int constipated; /* Throttle status for outgoing */
155 struct sk_buff *skb; /* Frame being sent */
156 struct sk_buff_head skb_list; /* Queued frames */
157 /* Data handling callback */
158 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
159 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
160 struct net_device *net; /* network interface, if created */
163 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
168 * DLCI 0 is used to pass control blocks out of band of the data
169 * flow (and with a higher link priority). One command can be outstanding
170 * at a time and we use this structure to manage them. They are created
171 * and destroyed by the user context, and updated by the receive paths
176 u8 cmd; /* Command we are issuing */
177 u8 *data; /* Data for the command in case we retransmit */
178 int len; /* Length of block for retransmission */
179 int done; /* Done flag */
180 int error; /* Error if any */
184 * Each GSM mux we have is represented by this structure. If we are
185 * operating as an ldisc then we use this structure as our ldisc
186 * state. We need to sort out lifetimes and locking with respect
187 * to the gsm mux array. For now we don't free DLCI objects that
188 * have been instantiated until the mux itself is terminated.
190 * To consider further: tty open versus mux shutdown.
194 struct tty_struct *tty; /* The tty our ldisc is bound to */
200 /* Events on the GSM channel */
201 wait_queue_head_t event;
203 /* Bits for GSM mode decoding */
210 #define GSM_ADDRESS 2
211 #define GSM_CONTROL 3
215 #define GSM_OVERRUN 7
220 unsigned int address;
227 u8 *txframe; /* TX framing buffer */
229 /* Methods for the receiver side */
230 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
232 /* And transmit side */
233 int (*output)(struct gsm_mux *mux, u8 *data, int len);
238 int initiator; /* Did we initiate connection */
239 int dead; /* Has the mux been shut down */
240 struct gsm_dlci *dlci[NUM_DLCI];
241 int constipated; /* Asked by remote to shut up */
244 unsigned int tx_bytes; /* TX data outstanding */
245 #define TX_THRESH_HI 8192
246 #define TX_THRESH_LO 2048
247 struct list_head tx_list; /* Pending data packets */
249 /* Control messages */
250 struct timer_list t2_timer; /* Retransmit timer for commands */
251 int cretries; /* Command retry counter */
252 struct gsm_control *pending_cmd;/* Our current pending command */
253 spinlock_t control_lock; /* Protects the pending command */
256 int adaption; /* 1 or 2 supported */
257 u8 ftype; /* UI or UIH */
258 int t1, t2; /* Timers in 1/100th of a sec */
259 int n2; /* Retry count */
261 /* Statistics (not currently exposed) */
262 unsigned long bad_fcs;
263 unsigned long malformed;
264 unsigned long io_error;
265 unsigned long bad_size;
266 unsigned long unsupported;
271 * Mux objects - needed so that we can translate a tty index into the
272 * relevant mux and DLCI.
275 #define MAX_MUX 4 /* 256 minors */
276 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
277 static spinlock_t gsm_mux_lock;
279 static struct tty_driver *gsm_tty_driver;
282 * This section of the driver logic implements the GSM encodings
283 * both the basic and the 'advanced'. Reliable transport is not
291 /* I is special: the rest are ..*/
302 /* Channel commands */
304 #define CMD_TEST 0x11
307 #define CMD_FCOFF 0x31
310 #define CMD_FCON 0x51
315 /* Virtual modem bits */
322 #define GSM0_SOF 0xF9
323 #define GSM1_SOF 0x7E
324 #define GSM1_ESCAPE 0x7D
325 #define GSM1_ESCAPE_BITS 0x20
329 static const struct tty_port_operations gsm_port_ops;
332 * CRC table for GSM 0710
335 static const u8 gsm_fcs8[256] = {
336 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
337 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
338 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
339 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
340 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
341 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
342 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
343 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
344 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
345 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
346 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
347 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
348 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
349 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
350 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
351 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
352 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
353 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
354 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
355 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
356 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
357 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
358 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
359 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
360 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
361 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
362 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
363 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
364 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
365 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
366 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
367 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370 #define INIT_FCS 0xFF
371 #define GOOD_FCS 0xCF
374 * gsm_fcs_add - update FCS
378 * Update the FCS to include c. Uses the algorithm in the specification
382 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384 return gsm_fcs8[fcs ^ c];
388 * gsm_fcs_add_block - update FCS for a block
391 * @len: length of buffer
393 * Update the FCS to include c. Uses the algorithm in the specification
397 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400 fcs = gsm_fcs8[fcs ^ *c++];
405 * gsm_read_ea - read a byte into an EA
406 * @val: variable holding value
407 * c: byte going into the EA
409 * Processes one byte of an EA. Updates the passed variable
410 * and returns 1 if the EA is now completely read
413 static int gsm_read_ea(unsigned int *val, u8 c)
415 /* Add the next 7 bits into the value */
418 /* Was this the last byte of the EA 1 = yes*/
423 * gsm_encode_modem - encode modem data bits
424 * @dlci: DLCI to encode from
426 * Returns the correct GSM encoded modem status bits (6 bit field) for
427 * the current status of the DLCI and attached tty object
430 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433 /* FC is true flow control not modem bits */
436 if (dlci->modem_tx & TIOCM_DTR)
437 modembits |= MDM_RTC;
438 if (dlci->modem_tx & TIOCM_RTS)
439 modembits |= MDM_RTR;
440 if (dlci->modem_tx & TIOCM_RI)
442 if (dlci->modem_tx & TIOCM_CD)
448 * gsm_print_packet - display a frame for debug
449 * @hdr: header to print before decode
450 * @addr: address EA from the frame
451 * @cr: C/R bit from the frame
452 * @control: control including PF bit
453 * @data: following data bytes
454 * @dlen: length of data
456 * Displays a packet in human readable format for debugging purposes. The
457 * style is based on amateur radio LAP-B dump display.
460 static void gsm_print_packet(const char *hdr, int addr, int cr,
461 u8 control, const u8 *data, int dlen)
466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468 switch (control & ~PF) {
488 if (!(control & 0x01)) {
489 pr_cont("I N(S)%d N(R)%d",
490 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
491 } else switch (control & 0x0F) {
493 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 pr_cont("[%02X]", control);
518 pr_cont("%02X ", *data++);
527 * Link level transmission side
531 * gsm_stuff_packet - bytestuff a packet
534 * @len: length of input
536 * Expand a buffer by bytestuffing it. The worst case size change
537 * is doubling and the caller is responsible for handing out
538 * suitable sized buffers.
541 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
545 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
546 || *input == XON || *input == XOFF) {
547 *output++ = GSM1_ESCAPE;
548 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 *output++ = *input++;
558 * gsm_send - send a control frame
560 * @addr: address for control frame
561 * @cr: command/response bit
562 * @control: control byte including PF bit
564 * Format up and transmit a control frame. These do not go via the
565 * queueing logic as they should be transmitted ahead of data when
568 * FIXME: Lock versus data TX path
571 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
577 switch (gsm->encoding) {
580 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[3] = EA; /* Length of data = 0 */
583 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
589 /* Control frame + packing (but not frame stuffing) in mode 1 */
590 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
593 /* Stuffing may double the size worst case */
594 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
595 /* Now add the SOF markers */
597 cbuf[len + 1] = GSM1_SOF;
598 /* FIXME: we can omit the lead one in many cases */
605 gsm->output(gsm, cbuf, len);
606 gsm_print_packet("-->", addr, cr, control, NULL, 0);
610 * gsm_response - send a control response
612 * @addr: address for control frame
613 * @control: control byte including PF bit
615 * Format up and transmit a link level response frame.
618 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620 gsm_send(gsm, addr, 0, control);
624 * gsm_command - send a control command
626 * @addr: address for control frame
627 * @control: control byte including PF bit
629 * Format up and transmit a link level command frame.
632 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634 gsm_send(gsm, addr, 1, control);
637 /* Data transmission */
639 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
642 * gsm_data_alloc - allocate data frame
644 * @addr: DLCI address
645 * @len: length excluding header and FCS
646 * @ctrl: control byte
648 * Allocate a new data buffer for sending frames with data. Space is left
649 * at the front for header bytes but that is treated as an implementation
650 * detail and not for the high level code to use
653 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
656 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
660 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
664 INIT_LIST_HEAD(&m->list);
669 * gsm_data_kick - poke the queue
672 * The tty device has called us to indicate that room has appeared in
673 * the transmit queue. Ram more data into the pipe if we have any
674 * If we have been flow-stopped by a CMD_FCOFF, then we can only
675 * send messages on DLCI0 until CMD_FCON
677 * FIXME: lock against link layer control transmissions
680 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
682 struct gsm_msg *msg, *nmsg;
685 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
686 if (gsm->constipated && msg->addr)
688 if (gsm->encoding != 0) {
689 gsm->txframe[0] = GSM1_SOF;
690 len = gsm_stuff_frame(msg->data,
691 gsm->txframe + 1, msg->len);
692 gsm->txframe[len + 1] = GSM1_SOF;
695 gsm->txframe[0] = GSM0_SOF;
696 memcpy(gsm->txframe + 1 , msg->data, msg->len);
697 gsm->txframe[msg->len + 1] = GSM0_SOF;
702 print_hex_dump_bytes("gsm_data_kick: ",
705 if (gsm->output(gsm, gsm->txframe, len) < 0)
707 /* FIXME: Can eliminate one SOF in many more cases */
708 gsm->tx_bytes -= msg->len;
710 list_del(&msg->list);
714 tty_port_tty_wakeup(&dlci->port);
718 for (i = 0; i < NUM_DLCI; i++)
720 tty_port_tty_wakeup(&gsm->dlci[i]->port);
726 * __gsm_data_queue - queue a UI or UIH frame
727 * @dlci: DLCI sending the data
728 * @msg: message queued
730 * Add data to the transmit queue and try and get stuff moving
731 * out of the mux tty if not already doing so. The Caller must hold
735 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
737 struct gsm_mux *gsm = dlci->gsm;
739 u8 *fcs = dp + msg->len;
741 /* Fill in the header */
742 if (gsm->encoding == 0) {
744 *--dp = (msg->len << 1) | EA;
746 *--dp = (msg->len >> 7); /* bits 7 - 15 */
747 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
753 *--dp = (msg->addr << 2) | 2 | EA;
755 *--dp = (msg->addr << 2) | EA;
756 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
757 /* Ugly protocol layering violation */
758 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
759 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
762 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
763 msg->data, msg->len);
765 /* Move the header back and adjust the length, also allow for the FCS
766 now tacked on the end */
767 msg->len += (msg->data - dp) + 1;
770 /* Add to the actual output queue */
771 list_add_tail(&msg->list, &gsm->tx_list);
772 gsm->tx_bytes += msg->len;
773 gsm_data_kick(gsm, dlci);
777 * gsm_data_queue - queue a UI or UIH frame
778 * @dlci: DLCI sending the data
779 * @msg: message queued
781 * Add data to the transmit queue and try and get stuff moving
782 * out of the mux tty if not already doing so. Take the
783 * the gsm tx lock and dlci lock.
786 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
789 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
790 __gsm_data_queue(dlci, msg);
791 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
795 * gsm_dlci_data_output - try and push data out of a DLCI
797 * @dlci: the DLCI to pull data from
799 * Pull data from a DLCI and send it into the transmit queue if there
800 * is data. Keep to the MRU of the mux. This path handles the usual tty
801 * interface which is a byte stream with optional modem data.
803 * Caller must hold the tx_lock of the mux.
806 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
810 int len, total_size, size;
811 int h = dlci->adaption - 1;
815 len = kfifo_len(dlci->fifo);
819 /* MTU/MRU count only the data bits */
825 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
826 /* FIXME: need a timer or something to kick this so it can't
827 get stuck with no work outstanding and no buffer free */
831 switch (dlci->adaption) {
832 case 1: /* Unstructured */
834 case 2: /* Unstructed with modem bits.
835 Always one byte as we never send inline break data */
836 *dp++ = gsm_encode_modem(dlci);
839 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
840 __gsm_data_queue(dlci, msg);
843 /* Bytes of data we used up */
848 * gsm_dlci_data_output_framed - try and push data out of a DLCI
850 * @dlci: the DLCI to pull data from
852 * Pull data from a DLCI and send it into the transmit queue if there
853 * is data. Keep to the MRU of the mux. This path handles framed data
854 * queued as skbuffs to the DLCI.
856 * Caller must hold the tx_lock of the mux.
859 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
860 struct gsm_dlci *dlci)
865 int last = 0, first = 0;
868 /* One byte per frame is used for B/F flags */
869 if (dlci->adaption == 4)
872 /* dlci->skb is locked by tx_lock */
873 if (dlci->skb == NULL) {
874 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
875 if (dlci->skb == NULL)
879 len = dlci->skb->len + overhead;
881 /* MTU/MRU count only the data bits */
882 if (len > gsm->mtu) {
883 if (dlci->adaption == 3) {
884 /* Over long frame, bin it */
885 dev_kfree_skb_any(dlci->skb);
893 size = len + overhead;
894 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
896 /* FIXME: need a timer or something to kick this so it can't
897 get stuck with no work outstanding and no buffer free */
899 skb_queue_tail(&dlci->skb_list, dlci->skb);
905 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
906 /* Flag byte to carry the start/end info */
907 *dp++ = last << 7 | first << 6 | 1; /* EA */
910 memcpy(dp, dlci->skb->data, len);
911 skb_pull(dlci->skb, len);
912 __gsm_data_queue(dlci, msg);
914 dev_kfree_skb_any(dlci->skb);
921 * gsm_dlci_data_sweep - look for data to send
924 * Sweep the GSM mux channels in priority order looking for ones with
925 * data to send. We could do with optimising this scan a bit. We aim
926 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
927 * TX_THRESH_LO we get called again
929 * FIXME: We should round robin between groups and in theory you can
930 * renegotiate DLCI priorities with optional stuff. Needs optimising.
933 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
936 /* Priority ordering: We should do priority with RR of the groups */
939 while (i < NUM_DLCI) {
940 struct gsm_dlci *dlci;
942 if (gsm->tx_bytes > TX_THRESH_HI)
945 if (dlci == NULL || dlci->constipated) {
949 if (dlci->adaption < 3 && !dlci->net)
950 len = gsm_dlci_data_output(gsm, dlci);
952 len = gsm_dlci_data_output_framed(gsm, dlci);
955 /* DLCI empty - try the next */
962 * gsm_dlci_data_kick - transmit if possible
963 * @dlci: DLCI to kick
965 * Transmit data from this DLCI if the queue is empty. We can't rely on
966 * a tty wakeup except when we filled the pipe so we need to fire off
967 * new data ourselves in other cases.
970 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
975 if (dlci->constipated)
978 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
979 /* If we have nothing running then we need to fire up */
980 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
981 if (dlci->gsm->tx_bytes == 0) {
983 gsm_dlci_data_output_framed(dlci->gsm, dlci);
985 gsm_dlci_data_output(dlci->gsm, dlci);
988 gsm_dlci_data_sweep(dlci->gsm);
989 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
993 * Control message processing
998 * gsm_control_reply - send a response frame to a control
1000 * @cmd: the command to use
1001 * @data: data to follow encoded info
1002 * @dlen: length of data
1004 * Encode up and queue a UI/UIH frame containing our response.
1007 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1010 struct gsm_msg *msg;
1011 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1014 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1015 msg->data[1] = (dlen << 1) | EA;
1016 memcpy(msg->data + 2, data, dlen);
1017 gsm_data_queue(gsm->dlci[0], msg);
1021 * gsm_process_modem - process received modem status
1022 * @tty: virtual tty bound to the DLCI
1023 * @dlci: DLCI to affect
1024 * @modem: modem bits (full EA)
1026 * Used when a modem control message or line state inline in adaption
1027 * layer 2 is processed. Sort out the local modem state and throttles
1030 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1031 u32 modem, int clen)
1037 /* The modem status command can either contain one octet (v.24 signals)
1038 or two octets (v.24 signals + break signals). The length field will
1039 either be 2 or 3 respectively. This is specified in section
1040 5.4.6.3.7 of the 27.010 mux spec. */
1043 modem = modem & 0x7f;
1046 modem = (modem >> 7) & 0x7f;
1049 /* Flow control/ready to communicate */
1050 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1051 if (fc && !dlci->constipated) {
1052 /* Need to throttle our output on this device */
1053 dlci->constipated = 1;
1054 } else if (!fc && dlci->constipated) {
1055 dlci->constipated = 0;
1056 gsm_dlci_data_kick(dlci);
1059 /* Map modem bits */
1060 if (modem & MDM_RTC)
1061 mlines |= TIOCM_DSR | TIOCM_DTR;
1062 if (modem & MDM_RTR)
1063 mlines |= TIOCM_RTS | TIOCM_CTS;
1069 /* Carrier drop -> hangup */
1071 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1076 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1077 dlci->modem_rx = mlines;
1081 * gsm_control_modem - modem status received
1083 * @data: data following command
1084 * @clen: command length
1086 * We have received a modem status control message. This is used by
1087 * the GSM mux protocol to pass virtual modem line status and optionally
1088 * to indicate break signals. Unpack it, convert to Linux representation
1089 * and if need be stuff a break message down the tty.
1092 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1094 unsigned int addr = 0;
1095 unsigned int modem = 0;
1096 unsigned int brk = 0;
1097 struct gsm_dlci *dlci;
1100 struct tty_struct *tty;
1102 while (gsm_read_ea(&addr, *dp++) == 0) {
1107 /* Must be at least one byte following the EA */
1113 /* Closed port, or invalid ? */
1114 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1116 dlci = gsm->dlci[addr];
1118 while (gsm_read_ea(&modem, *dp++) == 0) {
1125 while (gsm_read_ea(&brk, *dp++) == 0) {
1131 modem |= (brk & 0x7f);
1133 tty = tty_port_tty_get(&dlci->port);
1134 gsm_process_modem(tty, dlci, modem, clen);
1139 gsm_control_reply(gsm, CMD_MSC, data, clen);
1143 * gsm_control_rls - remote line status
1146 * @clen: data length
1148 * The modem sends us a two byte message on the control channel whenever
1149 * it wishes to send us an error state from the virtual link. Stuff
1150 * this into the uplink tty if present
1153 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1155 struct tty_port *port;
1156 unsigned int addr = 0;
1161 while (gsm_read_ea(&addr, *dp++) == 0) {
1166 /* Must be at least one byte following ea */
1171 /* Closed port, or invalid ? */
1172 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1176 if ((bits & 1) == 0)
1179 port = &gsm->dlci[addr]->port;
1182 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1184 tty_insert_flip_char(port, 0, TTY_PARITY);
1186 tty_insert_flip_char(port, 0, TTY_FRAME);
1188 tty_flip_buffer_push(port);
1190 gsm_control_reply(gsm, CMD_RLS, data, clen);
1193 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1196 * gsm_control_message - DLCI 0 control processing
1198 * @command: the command EA
1199 * @data: data beyond the command/length EAs
1202 * Input processor for control messages from the other end of the link.
1203 * Processes the incoming request and queues a response frame or an
1204 * NSC response if not supported
1207 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1211 unsigned long flags;
1215 struct gsm_dlci *dlci = gsm->dlci[0];
1216 /* Modem wishes to close down */
1220 gsm_dlci_begin_close(dlci);
1225 /* Modem wishes to test, reply with the data */
1226 gsm_control_reply(gsm, CMD_TEST, data, clen);
1229 /* Modem can accept data again */
1230 gsm->constipated = 0;
1231 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1232 /* Kick the link in case it is idling */
1233 spin_lock_irqsave(&gsm->tx_lock, flags);
1234 gsm_data_kick(gsm, NULL);
1235 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1238 /* Modem wants us to STFU */
1239 gsm->constipated = 1;
1240 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1243 /* Out of band modem line change indicator for a DLCI */
1244 gsm_control_modem(gsm, data, clen);
1247 /* Out of band error reception for a DLCI */
1248 gsm_control_rls(gsm, data, clen);
1251 /* Modem wishes to enter power saving state */
1252 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1254 /* Optional unsupported commands */
1255 case CMD_PN: /* Parameter negotiation */
1256 case CMD_RPN: /* Remote port negotiation */
1257 case CMD_SNC: /* Service negotiation command */
1259 /* Reply to bad commands with an NSC */
1261 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1267 * gsm_control_response - process a response to our control
1269 * @command: the command (response) EA
1270 * @data: data beyond the command/length EA
1273 * Process a response to an outstanding command. We only allow a single
1274 * control message in flight so this is fairly easy. All the clean up
1275 * is done by the caller, we just update the fields, flag it as done
1279 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1282 struct gsm_control *ctrl;
1283 unsigned long flags;
1285 spin_lock_irqsave(&gsm->control_lock, flags);
1287 ctrl = gsm->pending_cmd;
1288 /* Does the reply match our command */
1290 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1291 /* Our command was replied to, kill the retry timer */
1292 del_timer(&gsm->t2_timer);
1293 gsm->pending_cmd = NULL;
1294 /* Rejected by the other end */
1295 if (command == CMD_NSC)
1296 ctrl->error = -EOPNOTSUPP;
1298 wake_up(&gsm->event);
1300 spin_unlock_irqrestore(&gsm->control_lock, flags);
1304 * gsm_control_transmit - send control packet
1306 * @ctrl: frame to send
1308 * Send out a pending control command (called under control lock)
1311 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1313 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1316 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1317 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1318 gsm_data_queue(gsm->dlci[0], msg);
1322 * gsm_control_retransmit - retransmit a control frame
1323 * @data: pointer to our gsm object
1325 * Called off the T2 timer expiry in order to retransmit control frames
1326 * that have been lost in the system somewhere. The control_lock protects
1327 * us from colliding with another sender or a receive completion event.
1328 * In that situation the timer may still occur in a small window but
1329 * gsm->pending_cmd will be NULL and we just let the timer expire.
1332 static void gsm_control_retransmit(unsigned long data)
1334 struct gsm_mux *gsm = (struct gsm_mux *)data;
1335 struct gsm_control *ctrl;
1336 unsigned long flags;
1337 spin_lock_irqsave(&gsm->control_lock, flags);
1338 ctrl = gsm->pending_cmd;
1341 if (gsm->cretries == 0) {
1342 gsm->pending_cmd = NULL;
1343 ctrl->error = -ETIMEDOUT;
1345 spin_unlock_irqrestore(&gsm->control_lock, flags);
1346 wake_up(&gsm->event);
1349 gsm_control_transmit(gsm, ctrl);
1350 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1352 spin_unlock_irqrestore(&gsm->control_lock, flags);
1356 * gsm_control_send - send a control frame on DLCI 0
1357 * @gsm: the GSM channel
1358 * @command: command to send including CR bit
1359 * @data: bytes of data (must be kmalloced)
1360 * @len: length of the block to send
1362 * Queue and dispatch a control command. Only one command can be
1363 * active at a time. In theory more can be outstanding but the matching
1364 * gets really complicated so for now stick to one outstanding.
1367 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1368 unsigned int command, u8 *data, int clen)
1370 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1372 unsigned long flags;
1376 wait_event(gsm->event, gsm->pending_cmd == NULL);
1377 spin_lock_irqsave(&gsm->control_lock, flags);
1378 if (gsm->pending_cmd != NULL) {
1379 spin_unlock_irqrestore(&gsm->control_lock, flags);
1382 ctrl->cmd = command;
1385 gsm->pending_cmd = ctrl;
1387 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1388 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1391 gsm->cretries = gsm->n2;
1393 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1394 gsm_control_transmit(gsm, ctrl);
1395 spin_unlock_irqrestore(&gsm->control_lock, flags);
1400 * gsm_control_wait - wait for a control to finish
1402 * @control: control we are waiting on
1404 * Waits for the control to complete or time out. Frees any used
1405 * resources and returns 0 for success, or an error if the remote
1406 * rejected or ignored the request.
1409 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1412 wait_event(gsm->event, control->done == 1);
1413 err = control->error;
1420 * DLCI level handling: Needs krefs
1424 * State transitions and timers
1428 * gsm_dlci_close - a DLCI has closed
1429 * @dlci: DLCI that closed
1431 * Perform processing when moving a DLCI into closed state. If there
1432 * is an attached tty this is hung up
1435 static void gsm_dlci_close(struct gsm_dlci *dlci)
1437 del_timer(&dlci->t1);
1439 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1440 dlci->state = DLCI_CLOSED;
1441 if (dlci->addr != 0) {
1442 tty_port_tty_hangup(&dlci->port, false);
1443 kfifo_reset(dlci->fifo);
1445 dlci->gsm->dead = 1;
1446 wake_up(&dlci->gsm->event);
1447 /* A DLCI 0 close is a MUX termination so we need to kick that
1448 back to userspace somehow */
1452 * gsm_dlci_open - a DLCI has opened
1453 * @dlci: DLCI that opened
1455 * Perform processing when moving a DLCI into open state.
1458 static void gsm_dlci_open(struct gsm_dlci *dlci)
1460 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1462 del_timer(&dlci->t1);
1463 /* This will let a tty open continue */
1464 dlci->state = DLCI_OPEN;
1466 pr_debug("DLCI %d goes open.\n", dlci->addr);
1467 wake_up(&dlci->gsm->event);
1471 * gsm_dlci_t1 - T1 timer expiry
1472 * @dlci: DLCI that opened
1474 * The T1 timer handles retransmits of control frames (essentially of
1475 * SABM and DISC). We resend the command until the retry count runs out
1476 * in which case an opening port goes back to closed and a closing port
1477 * is simply put into closed state (any further frames from the other
1478 * end will get a DM response)
1480 * Some control dlci can stay in ADM mode with other dlci working just
1481 * fine. In that case we can just keep the control dlci open after the
1482 * DLCI_OPENING retries time out.
1485 static void gsm_dlci_t1(unsigned long data)
1487 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1488 struct gsm_mux *gsm = dlci->gsm;
1490 switch (dlci->state) {
1493 if (dlci->retries) {
1494 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1495 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1496 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1498 pr_info("DLCI %d opening in ADM mode.\n",
1500 dlci->mode = DLCI_MODE_ADM;
1501 gsm_dlci_open(dlci);
1503 gsm_dlci_close(dlci);
1509 if (dlci->retries) {
1510 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1511 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1513 gsm_dlci_close(dlci);
1519 * gsm_dlci_begin_open - start channel open procedure
1520 * @dlci: DLCI to open
1522 * Commence opening a DLCI from the Linux side. We issue SABM messages
1523 * to the modem which should then reply with a UA or ADM, at which point
1524 * we will move into open state. Opening is done asynchronously with retry
1525 * running off timers and the responses.
1528 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1530 struct gsm_mux *gsm = dlci->gsm;
1531 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1533 dlci->retries = gsm->n2;
1534 dlci->state = DLCI_OPENING;
1535 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1536 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1540 * gsm_dlci_begin_close - start channel open procedure
1541 * @dlci: DLCI to open
1543 * Commence closing a DLCI from the Linux side. We issue DISC messages
1544 * to the modem which should then reply with a UA, at which point we
1545 * will move into closed state. Closing is done asynchronously with retry
1546 * off timers. We may also receive a DM reply from the other end which
1547 * indicates the channel was already closed.
1550 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1552 struct gsm_mux *gsm = dlci->gsm;
1553 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1555 dlci->retries = gsm->n2;
1556 dlci->state = DLCI_CLOSING;
1557 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1558 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1562 * gsm_dlci_data - data arrived
1564 * @data: block of bytes received
1565 * @len: length of received block
1567 * A UI or UIH frame has arrived which contains data for a channel
1568 * other than the control channel. If the relevant virtual tty is
1569 * open we shovel the bits down it, if not we drop them.
1572 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1575 struct tty_port *port = &dlci->port;
1576 struct tty_struct *tty;
1577 unsigned int modem = 0;
1581 pr_debug("%d bytes for tty\n", len);
1582 switch (dlci->adaption) {
1583 /* Unsupported types */
1584 /* Packetised interruptible data */
1587 /* Packetised uininterruptible voice/data */
1590 /* Asynchronous serial with line state in each frame */
1592 while (gsm_read_ea(&modem, *data++) == 0) {
1597 tty = tty_port_tty_get(port);
1599 gsm_process_modem(tty, dlci, modem, clen);
1602 /* Line state will go via DLCI 0 controls only */
1605 tty_insert_flip_string(port, data, len);
1606 tty_flip_buffer_push(port);
1611 * gsm_dlci_control - data arrived on control channel
1613 * @data: block of bytes received
1614 * @len: length of received block
1616 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1617 * control channel. This should contain a command EA followed by
1618 * control data bytes. The command EA contains a command/response bit
1619 * and we divide up the work accordingly.
1622 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1624 /* See what command is involved */
1625 unsigned int command = 0;
1627 if (gsm_read_ea(&command, *data++) == 1) {
1630 /* FIXME: this is properly an EA */
1632 /* Malformed command ? */
1636 gsm_control_message(dlci->gsm, command,
1639 gsm_control_response(dlci->gsm, command,
1647 * Allocate/Free DLCI channels
1651 * gsm_dlci_alloc - allocate a DLCI
1653 * @addr: address of the DLCI
1655 * Allocate and install a new DLCI object into the GSM mux.
1657 * FIXME: review locking races
1660 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1662 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1665 spin_lock_init(&dlci->lock);
1666 mutex_init(&dlci->mutex);
1667 dlci->fifo = &dlci->_fifo;
1668 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1673 skb_queue_head_init(&dlci->skb_list);
1674 init_timer(&dlci->t1);
1675 dlci->t1.function = gsm_dlci_t1;
1676 dlci->t1.data = (unsigned long)dlci;
1677 tty_port_init(&dlci->port);
1678 dlci->port.ops = &gsm_port_ops;
1681 dlci->adaption = gsm->adaption;
1682 dlci->state = DLCI_CLOSED;
1684 dlci->data = gsm_dlci_data;
1686 dlci->data = gsm_dlci_command;
1687 gsm->dlci[addr] = dlci;
1692 * gsm_dlci_free - free DLCI
1693 * @dlci: DLCI to free
1699 static void gsm_dlci_free(struct tty_port *port)
1701 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1703 del_timer_sync(&dlci->t1);
1704 dlci->gsm->dlci[dlci->addr] = NULL;
1705 kfifo_free(dlci->fifo);
1706 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1707 dev_kfree_skb(dlci->skb);
1711 static inline void dlci_get(struct gsm_dlci *dlci)
1713 tty_port_get(&dlci->port);
1716 static inline void dlci_put(struct gsm_dlci *dlci)
1718 tty_port_put(&dlci->port);
1721 static void gsm_destroy_network(struct gsm_dlci *dlci);
1724 * gsm_dlci_release - release DLCI
1725 * @dlci: DLCI to destroy
1727 * Release a DLCI. Actual free is deferred until either
1728 * mux is closed or tty is closed - whichever is last.
1732 static void gsm_dlci_release(struct gsm_dlci *dlci)
1734 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1736 mutex_lock(&dlci->mutex);
1737 gsm_destroy_network(dlci);
1738 mutex_unlock(&dlci->mutex);
1742 tty_port_tty_set(&dlci->port, NULL);
1745 dlci->state = DLCI_CLOSED;
1750 * LAPBish link layer logic
1754 * gsm_queue - a GSM frame is ready to process
1755 * @gsm: pointer to our gsm mux
1757 * At this point in time a frame has arrived and been demangled from
1758 * the line encoding. All the differences between the encodings have
1759 * been handled below us and the frame is unpacked into the structures.
1760 * The fcs holds the header FCS but any data FCS must be added here.
1763 static void gsm_queue(struct gsm_mux *gsm)
1765 struct gsm_dlci *dlci;
1768 /* We have to sneak a look at the packet body to do the FCS.
1769 A somewhat layering violation in the spec */
1771 if ((gsm->control & ~PF) == UI)
1772 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1773 if (gsm->encoding == 0) {
1774 /* WARNING: gsm->received_fcs is used for
1775 gsm->encoding = 0 only.
1776 In this case it contain the last piece of data
1777 required to generate final CRC */
1778 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1780 if (gsm->fcs != GOOD_FCS) {
1783 pr_debug("BAD FCS %02x\n", gsm->fcs);
1786 address = gsm->address >> 1;
1787 if (address >= NUM_DLCI)
1790 cr = gsm->address & 1; /* C/R bit */
1792 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1794 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1795 dlci = gsm->dlci[address];
1797 switch (gsm->control) {
1802 dlci = gsm_dlci_alloc(gsm, address);
1806 gsm_response(gsm, address, DM);
1808 gsm_response(gsm, address, UA);
1809 gsm_dlci_open(dlci);
1815 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1816 gsm_response(gsm, address, DM);
1819 /* Real close complete */
1820 gsm_response(gsm, address, UA);
1821 gsm_dlci_close(dlci);
1825 if (cr == 0 || dlci == NULL)
1827 switch (dlci->state) {
1829 gsm_dlci_close(dlci);
1832 gsm_dlci_open(dlci);
1836 case DM: /* DM can be valid unsolicited */
1842 gsm_dlci_close(dlci);
1852 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1853 gsm_command(gsm, address, DM|PF);
1856 dlci->data(dlci, gsm->buf, gsm->len);
1869 * gsm0_receive - perform processing for non-transparency
1870 * @gsm: gsm data for this ldisc instance
1873 * Receive bytes in gsm mode 0
1876 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1880 switch (gsm->state) {
1881 case GSM_SEARCH: /* SOF marker */
1882 if (c == GSM0_SOF) {
1883 gsm->state = GSM_ADDRESS;
1886 gsm->fcs = INIT_FCS;
1889 case GSM_ADDRESS: /* Address EA */
1890 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1891 if (gsm_read_ea(&gsm->address, c))
1892 gsm->state = GSM_CONTROL;
1894 case GSM_CONTROL: /* Control Byte */
1895 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 gsm->state = GSM_LEN0;
1899 case GSM_LEN0: /* Length EA */
1900 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1901 if (gsm_read_ea(&gsm->len, c)) {
1902 if (gsm->len > gsm->mru) {
1904 gsm->state = GSM_SEARCH;
1909 gsm->state = GSM_FCS;
1911 gsm->state = GSM_DATA;
1914 gsm->state = GSM_LEN1;
1917 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1919 gsm->len |= len << 7;
1920 if (gsm->len > gsm->mru) {
1922 gsm->state = GSM_SEARCH;
1927 gsm->state = GSM_FCS;
1929 gsm->state = GSM_DATA;
1931 case GSM_DATA: /* Data */
1932 gsm->buf[gsm->count++] = c;
1933 if (gsm->count == gsm->len)
1934 gsm->state = GSM_FCS;
1936 case GSM_FCS: /* FCS follows the packet */
1937 gsm->received_fcs = c;
1939 gsm->state = GSM_SSOF;
1942 if (c == GSM0_SOF) {
1943 gsm->state = GSM_SEARCH;
1951 * gsm1_receive - perform processing for non-transparency
1952 * @gsm: gsm data for this ldisc instance
1955 * Receive bytes in mode 1 (Advanced option)
1958 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1960 if (c == GSM1_SOF) {
1961 /* EOF is only valid in frame if we have got to the data state
1962 and received at least one byte (the FCS) */
1963 if (gsm->state == GSM_DATA && gsm->count) {
1964 /* Extract the FCS */
1966 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1967 gsm->len = gsm->count;
1969 gsm->state = GSM_START;
1972 /* Any partial frame was a runt so go back to start */
1973 if (gsm->state != GSM_START) {
1975 gsm->state = GSM_START;
1977 /* A SOF in GSM_START means we are still reading idling or
1982 if (c == GSM1_ESCAPE) {
1987 /* Only an unescaped SOF gets us out of GSM search */
1988 if (gsm->state == GSM_SEARCH)
1992 c ^= GSM1_ESCAPE_BITS;
1995 switch (gsm->state) {
1996 case GSM_START: /* First byte after SOF */
1998 gsm->state = GSM_ADDRESS;
1999 gsm->fcs = INIT_FCS;
2001 case GSM_ADDRESS: /* Address continuation */
2002 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2003 if (gsm_read_ea(&gsm->address, c))
2004 gsm->state = GSM_CONTROL;
2006 case GSM_CONTROL: /* Control Byte */
2007 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2010 gsm->state = GSM_DATA;
2012 case GSM_DATA: /* Data */
2013 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2014 gsm->state = GSM_OVERRUN;
2017 gsm->buf[gsm->count++] = c;
2019 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2025 * gsm_error - handle tty error
2027 * @data: byte received (may be invalid)
2028 * @flag: error received
2030 * Handle an error in the receipt of data for a frame. Currently we just
2031 * go back to hunting for a SOF.
2033 * FIXME: better diagnostics ?
2036 static void gsm_error(struct gsm_mux *gsm,
2037 unsigned char data, unsigned char flag)
2039 gsm->state = GSM_SEARCH;
2043 static int gsm_disconnect(struct gsm_mux *gsm)
2045 struct gsm_dlci *dlci = gsm->dlci[0];
2046 struct gsm_control *gc;
2051 /* In theory disconnecting DLCI 0 is sufficient but for some
2052 modems this is apparently not the case. */
2053 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2055 gsm_control_wait(gsm, gc);
2057 del_timer_sync(&gsm->t2_timer);
2058 /* Now we are sure T2 has stopped */
2060 gsm_dlci_begin_close(dlci);
2061 wait_event_interruptible(gsm->event,
2062 dlci->state == DLCI_CLOSED);
2064 if (signal_pending(current))
2071 * gsm_cleanup_mux - generic GSM protocol cleanup
2074 * Clean up the bits of the mux which are the same for all framing
2075 * protocols. Remove the mux from the mux table, stop all the timers
2076 * and then shut down each device hanging up the channels as we go.
2079 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2082 struct gsm_dlci *dlci = gsm->dlci[0];
2083 struct gsm_msg *txq, *ntxq;
2087 spin_lock(&gsm_mux_lock);
2088 for (i = 0; i < MAX_MUX; i++) {
2089 if (gsm_mux[i] == gsm) {
2094 spin_unlock(&gsm_mux_lock);
2095 /* open failed before registering => nothing to do */
2099 del_timer_sync(&gsm->t2_timer);
2100 /* Now we are sure T2 has stopped */
2104 /* Free up any link layer users */
2105 mutex_lock(&gsm->mutex);
2106 for (i = 0; i < NUM_DLCI; i++)
2108 gsm_dlci_release(gsm->dlci[i]);
2109 mutex_unlock(&gsm->mutex);
2110 /* Now wipe the queues */
2111 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2113 INIT_LIST_HEAD(&gsm->tx_list);
2117 * gsm_activate_mux - generic GSM setup
2120 * Set up the bits of the mux which are the same for all framing
2121 * protocols. Add the mux to the mux table so it can be opened and
2122 * finally kick off connecting to DLCI 0 on the modem.
2125 static int gsm_activate_mux(struct gsm_mux *gsm)
2127 struct gsm_dlci *dlci;
2130 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
2131 init_waitqueue_head(&gsm->event);
2132 spin_lock_init(&gsm->control_lock);
2133 spin_lock_init(&gsm->tx_lock);
2135 if (gsm->encoding == 0)
2136 gsm->receive = gsm0_receive;
2138 gsm->receive = gsm1_receive;
2139 gsm->error = gsm_error;
2141 spin_lock(&gsm_mux_lock);
2142 for (i = 0; i < MAX_MUX; i++) {
2143 if (gsm_mux[i] == NULL) {
2149 spin_unlock(&gsm_mux_lock);
2153 dlci = gsm_dlci_alloc(gsm, 0);
2156 gsm->dead = 0; /* Tty opens are now permissible */
2161 * gsm_free_mux - free up a mux
2164 * Dispose of allocated resources for a dead mux
2166 static void gsm_free_mux(struct gsm_mux *gsm)
2168 kfree(gsm->txframe);
2174 * gsm_free_muxr - free up a mux
2177 * Dispose of allocated resources for a dead mux
2179 static void gsm_free_muxr(struct kref *ref)
2181 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2185 static inline void mux_get(struct gsm_mux *gsm)
2187 kref_get(&gsm->ref);
2190 static inline void mux_put(struct gsm_mux *gsm)
2192 kref_put(&gsm->ref, gsm_free_muxr);
2196 * gsm_alloc_mux - allocate a mux
2198 * Creates a new mux ready for activation.
2201 static struct gsm_mux *gsm_alloc_mux(void)
2203 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2206 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2207 if (gsm->buf == NULL) {
2211 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2212 if (gsm->txframe == NULL) {
2217 spin_lock_init(&gsm->lock);
2218 mutex_init(&gsm->mutex);
2219 kref_init(&gsm->ref);
2220 INIT_LIST_HEAD(&gsm->tx_list);
2228 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2230 gsm->dead = 1; /* Avoid early tty opens */
2236 * gsmld_output - write to link
2238 * @data: bytes to output
2241 * Write a block of data from the GSM mux to the data channel. This
2242 * will eventually be serialized from above but at the moment isn't.
2245 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2247 if (tty_write_room(gsm->tty) < len) {
2248 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2252 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2254 gsm->tty->ops->write(gsm->tty, data, len);
2259 * gsmld_attach_gsm - mode set up
2260 * @tty: our tty structure
2263 * Set up the MUX for basic mode and commence connecting to the
2264 * modem. Currently called from the line discipline set up but
2265 * will need moving to an ioctl path.
2268 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2272 gsm->tty = tty_kref_get(tty);
2273 gsm->output = gsmld_output;
2274 ret = gsm_activate_mux(gsm);
2276 tty_kref_put(gsm->tty);
2278 /* Don't register device 0 - this is the control channel and not
2279 a usable tty interface */
2280 base = gsm->num << 6; /* Base for this MUX */
2281 for (i = 1; i < NUM_DLCI; i++)
2282 tty_register_device(gsm_tty_driver, base + i, NULL);
2289 * gsmld_detach_gsm - stop doing 0710 mux
2290 * @tty: tty attached to the mux
2293 * Shutdown and then clean up the resources used by the line discipline
2296 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2299 int base = gsm->num << 6; /* Base for this MUX */
2301 WARN_ON(tty != gsm->tty);
2302 for (i = 1; i < NUM_DLCI; i++)
2303 tty_unregister_device(gsm_tty_driver, base + i);
2304 gsm_cleanup_mux(gsm);
2305 tty_kref_put(gsm->tty);
2309 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2310 char *fp, int count)
2312 struct gsm_mux *gsm = tty->disc_data;
2313 const unsigned char *dp;
2316 char flags = TTY_NORMAL;
2319 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2322 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2327 gsm->receive(gsm, *dp);
2333 gsm->error(gsm, *dp, flags);
2336 WARN_ONCE(1, "%s: unknown flag %d\n",
2337 tty_name(tty), flags);
2341 /* FASYNC if needed ? */
2342 /* If clogged call tty_throttle(tty); */
2346 * gsmld_flush_buffer - clean input queue
2347 * @tty: terminal device
2349 * Flush the input buffer. Called when the line discipline is
2350 * being closed, when the tty layer wants the buffer flushed (eg
2354 static void gsmld_flush_buffer(struct tty_struct *tty)
2359 * gsmld_close - close the ldisc for this tty
2362 * Called from the terminal layer when this line discipline is
2363 * being shut down, either because of a close or becsuse of a
2364 * discipline change. The function will not be called while other
2365 * ldisc methods are in progress.
2368 static void gsmld_close(struct tty_struct *tty)
2370 struct gsm_mux *gsm = tty->disc_data;
2372 gsmld_detach_gsm(tty, gsm);
2374 gsmld_flush_buffer(tty);
2375 /* Do other clean up here */
2380 * gsmld_open - open an ldisc
2381 * @tty: terminal to open
2383 * Called when this line discipline is being attached to the
2384 * terminal device. Can sleep. Called serialized so that no
2385 * other events will occur in parallel. No further open will occur
2389 static int gsmld_open(struct tty_struct *tty)
2391 struct gsm_mux *gsm;
2394 if (tty->ops->write == NULL)
2397 /* Attach our ldisc data */
2398 gsm = gsm_alloc_mux();
2402 tty->disc_data = gsm;
2403 tty->receive_room = 65536;
2405 /* Attach the initial passive connection */
2408 ret = gsmld_attach_gsm(tty, gsm);
2410 gsm_cleanup_mux(gsm);
2417 * gsmld_write_wakeup - asynchronous I/O notifier
2420 * Required for the ptys, serial driver etc. since processes
2421 * that attach themselves to the master and rely on ASYNC
2422 * IO must be woken up
2425 static void gsmld_write_wakeup(struct tty_struct *tty)
2427 struct gsm_mux *gsm = tty->disc_data;
2428 unsigned long flags;
2431 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2432 spin_lock_irqsave(&gsm->tx_lock, flags);
2433 gsm_data_kick(gsm, NULL);
2434 if (gsm->tx_bytes < TX_THRESH_LO) {
2435 gsm_dlci_data_sweep(gsm);
2437 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2441 * gsmld_read - read function for tty
2443 * @file: file object
2444 * @buf: userspace buffer pointer
2447 * Perform reads for the line discipline. We are guaranteed that the
2448 * line discipline will not be closed under us but we may get multiple
2449 * parallel readers and must handle this ourselves. We may also get
2450 * a hangup. Always called in user context, may sleep.
2452 * This code must be sure never to sleep through a hangup.
2455 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2456 unsigned char __user *buf, size_t nr)
2462 * gsmld_write - write function for tty
2464 * @file: file object
2465 * @buf: userspace buffer pointer
2468 * Called when the owner of the device wants to send a frame
2469 * itself (or some other control data). The data is transferred
2470 * as-is and must be properly framed and checksummed as appropriate
2471 * by userspace. Frames are either sent whole or not at all as this
2472 * avoids pain user side.
2475 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2476 const unsigned char *buf, size_t nr)
2478 int space = tty_write_room(tty);
2480 return tty->ops->write(tty, buf, nr);
2481 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2486 * gsmld_poll - poll method for N_GSM0710
2487 * @tty: terminal device
2488 * @file: file accessing it
2491 * Called when the line discipline is asked to poll() for data or
2492 * for special events. This code is not serialized with respect to
2493 * other events save open/close.
2495 * This code must be sure never to sleep through a hangup.
2496 * Called without the kernel lock held - fine
2499 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2502 unsigned int mask = 0;
2503 struct gsm_mux *gsm = tty->disc_data;
2505 poll_wait(file, &tty->read_wait, wait);
2506 poll_wait(file, &tty->write_wait, wait);
2507 if (tty_hung_up_p(file))
2509 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2510 mask |= POLLOUT | POLLWRNORM;
2516 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2517 struct gsm_config *c)
2520 int need_restart = 0;
2522 /* Stuff we don't support yet - UI or I frame transport, windowing */
2523 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2525 /* Check the MRU/MTU range looks sane */
2526 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2530 if (c->encapsulation > 1) /* Basic, advanced, no I */
2532 if (c->initiator > 1)
2534 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2537 * See what is needed for reconfiguration
2541 if (c->t1 != 0 && c->t1 != gsm->t1)
2543 if (c->t2 != 0 && c->t2 != gsm->t2)
2545 if (c->encapsulation != gsm->encoding)
2547 if (c->adaption != gsm->adaption)
2550 if (c->initiator != gsm->initiator)
2552 if (c->mru != gsm->mru)
2554 if (c->mtu != gsm->mtu)
2558 * Close down what is needed, restart and initiate the new
2562 if (need_close || need_restart) {
2565 ret = gsm_disconnect(gsm);
2571 gsm_cleanup_mux(gsm);
2573 gsm->initiator = c->initiator;
2576 gsm->encoding = c->encapsulation;
2577 gsm->adaption = c->adaption;
2590 /* FIXME: We need to separate activation/deactivation from adding
2591 and removing from the mux array */
2593 gsm_activate_mux(gsm);
2594 if (gsm->initiator && need_close)
2595 gsm_dlci_begin_open(gsm->dlci[0]);
2599 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2600 unsigned int cmd, unsigned long arg)
2602 struct gsm_config c;
2603 struct gsm_mux *gsm = tty->disc_data;
2606 case GSMIOC_GETCONF:
2607 memset(&c, 0, sizeof(c));
2608 c.adaption = gsm->adaption;
2609 c.encapsulation = gsm->encoding;
2610 c.initiator = gsm->initiator;
2613 c.t3 = 0; /* Not supported */
2615 if (gsm->ftype == UIH)
2619 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2623 if (copy_to_user((void *)arg, &c, sizeof(c)))
2626 case GSMIOC_SETCONF:
2627 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2629 return gsmld_config(tty, gsm, &c);
2631 return n_tty_ioctl_helper(tty, file, cmd, arg);
2635 #ifdef CONFIG_COMPAT
2636 static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file,
2637 unsigned int cmd, unsigned long arg)
2639 return gsmld_ioctl(tty, file, cmd, arg);
2648 static int gsm_mux_net_open(struct net_device *net)
2650 pr_debug("%s called\n", __func__);
2651 netif_start_queue(net);
2655 static int gsm_mux_net_close(struct net_device *net)
2657 netif_stop_queue(net);
2661 static void dlci_net_free(struct gsm_dlci *dlci)
2667 dlci->adaption = dlci->prev_adaption;
2668 dlci->data = dlci->prev_data;
2669 free_netdev(dlci->net);
2672 static void net_free(struct kref *ref)
2674 struct gsm_mux_net *mux_net;
2675 struct gsm_dlci *dlci;
2677 mux_net = container_of(ref, struct gsm_mux_net, ref);
2678 dlci = mux_net->dlci;
2681 unregister_netdev(dlci->net);
2682 dlci_net_free(dlci);
2686 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2688 kref_get(&mux_net->ref);
2691 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2693 kref_put(&mux_net->ref, net_free);
2696 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2697 struct net_device *net)
2699 struct gsm_mux_net *mux_net = netdev_priv(net);
2700 struct gsm_dlci *dlci = mux_net->dlci;
2701 muxnet_get(mux_net);
2703 skb_queue_head(&dlci->skb_list, skb);
2704 net->stats.tx_packets++;
2705 net->stats.tx_bytes += skb->len;
2706 gsm_dlci_data_kick(dlci);
2707 /* And tell the kernel when the last transmit started. */
2708 netif_trans_update(net);
2709 muxnet_put(mux_net);
2710 return NETDEV_TX_OK;
2713 /* called when a packet did not ack after watchdogtimeout */
2714 static void gsm_mux_net_tx_timeout(struct net_device *net)
2716 /* Tell syslog we are hosed. */
2717 dev_dbg(&net->dev, "Tx timed out.\n");
2719 /* Update statistics */
2720 net->stats.tx_errors++;
2723 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2724 unsigned char *in_buf, int size)
2726 struct net_device *net = dlci->net;
2727 struct sk_buff *skb;
2728 struct gsm_mux_net *mux_net = netdev_priv(net);
2729 muxnet_get(mux_net);
2731 /* Allocate an sk_buff */
2732 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2734 /* We got no receive buffer. */
2735 net->stats.rx_dropped++;
2736 muxnet_put(mux_net);
2739 skb_reserve(skb, NET_IP_ALIGN);
2740 skb_put_data(skb, in_buf, size);
2743 skb->protocol = htons(ETH_P_IP);
2745 /* Ship it off to the kernel */
2748 /* update out statistics */
2749 net->stats.rx_packets++;
2750 net->stats.rx_bytes += size;
2751 muxnet_put(mux_net);
2755 static void gsm_mux_net_init(struct net_device *net)
2757 static const struct net_device_ops gsm_netdev_ops = {
2758 .ndo_open = gsm_mux_net_open,
2759 .ndo_stop = gsm_mux_net_close,
2760 .ndo_start_xmit = gsm_mux_net_start_xmit,
2761 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2764 net->netdev_ops = &gsm_netdev_ops;
2766 /* fill in the other fields */
2767 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2768 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2769 net->type = ARPHRD_NONE;
2770 net->tx_queue_len = 10;
2774 /* caller holds the dlci mutex */
2775 static void gsm_destroy_network(struct gsm_dlci *dlci)
2777 struct gsm_mux_net *mux_net;
2779 pr_debug("destroy network interface");
2782 mux_net = netdev_priv(dlci->net);
2783 muxnet_put(mux_net);
2787 /* caller holds the dlci mutex */
2788 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2792 struct net_device *net;
2793 struct gsm_mux_net *mux_net;
2795 if (!capable(CAP_NET_ADMIN))
2798 /* Already in a non tty mode */
2799 if (dlci->adaption > 2)
2802 if (nc->protocol != htons(ETH_P_IP))
2803 return -EPROTONOSUPPORT;
2805 if (nc->adaption != 3 && nc->adaption != 4)
2806 return -EPROTONOSUPPORT;
2808 pr_debug("create network interface");
2811 if (nc->if_name[0] != '\0')
2812 netname = nc->if_name;
2813 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2814 NET_NAME_UNKNOWN, gsm_mux_net_init);
2816 pr_err("alloc_netdev failed");
2819 net->mtu = dlci->gsm->mtu;
2821 net->max_mtu = dlci->gsm->mtu;
2822 mux_net = netdev_priv(net);
2823 mux_net->dlci = dlci;
2824 kref_init(&mux_net->ref);
2825 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2827 /* reconfigure dlci for network */
2828 dlci->prev_adaption = dlci->adaption;
2829 dlci->prev_data = dlci->data;
2830 dlci->adaption = nc->adaption;
2831 dlci->data = gsm_mux_rx_netchar;
2834 pr_debug("register netdev");
2835 retval = register_netdev(net);
2837 pr_err("network register fail %d\n", retval);
2838 dlci_net_free(dlci);
2841 return net->ifindex; /* return network index */
2844 /* Line discipline for real tty */
2845 static struct tty_ldisc_ops tty_ldisc_packet = {
2846 .owner = THIS_MODULE,
2847 .magic = TTY_LDISC_MAGIC,
2850 .close = gsmld_close,
2851 .flush_buffer = gsmld_flush_buffer,
2853 .write = gsmld_write,
2854 #ifdef CONFIG_COMPAT
2855 .compat_ioctl = gsmld_compat_ioctl,
2857 .ioctl = gsmld_ioctl,
2859 .receive_buf = gsmld_receive_buf,
2860 .write_wakeup = gsmld_write_wakeup
2869 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2872 struct gsm_control *ctrl;
2878 modembits[0] = len << 1 | EA; /* Data bytes */
2879 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2880 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2882 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2883 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2886 return gsm_control_wait(dlci->gsm, ctrl);
2889 static int gsm_carrier_raised(struct tty_port *port)
2891 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2892 struct gsm_mux *gsm = dlci->gsm;
2894 /* Not yet open so no carrier info */
2895 if (dlci->state != DLCI_OPEN)
2901 * Basic mode with control channel in ADM mode may not respond
2902 * to CMD_MSC at all and modem_rx is empty.
2904 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2908 return dlci->modem_rx & TIOCM_CD;
2911 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2913 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2914 unsigned int modem_tx = dlci->modem_tx;
2916 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2918 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2919 if (modem_tx != dlci->modem_tx) {
2920 dlci->modem_tx = modem_tx;
2921 gsmtty_modem_update(dlci, 0);
2925 static const struct tty_port_operations gsm_port_ops = {
2926 .carrier_raised = gsm_carrier_raised,
2927 .dtr_rts = gsm_dtr_rts,
2928 .destruct = gsm_dlci_free,
2931 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2933 struct gsm_mux *gsm;
2934 struct gsm_dlci *dlci;
2935 unsigned int line = tty->index;
2936 unsigned int mux = line >> 6;
2944 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2945 if (gsm_mux[mux] == NULL)
2947 if (line == 0 || line > 61) /* 62/63 reserved */
2952 /* If DLCI 0 is not yet fully open return an error.
2953 This is ok from a locking
2954 perspective as we don't have to worry about this
2956 mutex_lock(&gsm->mutex);
2957 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2958 mutex_unlock(&gsm->mutex);
2961 dlci = gsm->dlci[line];
2964 dlci = gsm_dlci_alloc(gsm, line);
2967 mutex_unlock(&gsm->mutex);
2970 ret = tty_port_install(&dlci->port, driver, tty);
2974 mutex_unlock(&gsm->mutex);
2979 dlci_get(gsm->dlci[0]);
2981 tty->driver_data = dlci;
2982 mutex_unlock(&gsm->mutex);
2987 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2989 struct gsm_dlci *dlci = tty->driver_data;
2990 struct tty_port *port = &dlci->port;
2993 tty_port_tty_set(port, tty);
2996 /* We could in theory open and close before we wait - eg if we get
2997 a DM straight back. This is ok as that will have caused a hangup */
2998 tty_port_set_initialized(port, 1);
2999 /* Start sending off SABM messages */
3000 gsm_dlci_begin_open(dlci);
3001 /* And wait for virtual carrier */
3002 return tty_port_block_til_ready(port, tty, filp);
3005 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3007 struct gsm_dlci *dlci = tty->driver_data;
3008 struct gsm_mux *gsm;
3012 if (dlci->state == DLCI_CLOSED)
3014 mutex_lock(&dlci->mutex);
3015 gsm_destroy_network(dlci);
3016 mutex_unlock(&dlci->mutex);
3018 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3020 gsm_dlci_begin_close(dlci);
3021 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3022 tty_port_lower_dtr_rts(&dlci->port);
3023 tty_port_close_end(&dlci->port, tty);
3024 tty_port_tty_set(&dlci->port, NULL);
3028 static void gsmtty_hangup(struct tty_struct *tty)
3030 struct gsm_dlci *dlci = tty->driver_data;
3031 if (dlci->state == DLCI_CLOSED)
3033 tty_port_hangup(&dlci->port);
3034 gsm_dlci_begin_close(dlci);
3037 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3041 struct gsm_dlci *dlci = tty->driver_data;
3042 if (dlci->state == DLCI_CLOSED)
3044 /* Stuff the bytes into the fifo queue */
3045 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3046 /* Need to kick the channel */
3047 gsm_dlci_data_kick(dlci);
3051 static int gsmtty_write_room(struct tty_struct *tty)
3053 struct gsm_dlci *dlci = tty->driver_data;
3054 if (dlci->state == DLCI_CLOSED)
3056 return TX_SIZE - kfifo_len(dlci->fifo);
3059 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3061 struct gsm_dlci *dlci = tty->driver_data;
3062 if (dlci->state == DLCI_CLOSED)
3064 return kfifo_len(dlci->fifo);
3067 static void gsmtty_flush_buffer(struct tty_struct *tty)
3069 struct gsm_dlci *dlci = tty->driver_data;
3070 if (dlci->state == DLCI_CLOSED)
3072 /* Caution needed: If we implement reliable transport classes
3073 then the data being transmitted can't simply be junked once
3074 it has first hit the stack. Until then we can just blow it
3076 kfifo_reset(dlci->fifo);
3077 /* Need to unhook this DLCI from the transmit queue logic */
3080 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3082 /* The FIFO handles the queue so the kernel will do the right
3083 thing waiting on chars_in_buffer before calling us. No work
3087 static int gsmtty_tiocmget(struct tty_struct *tty)
3089 struct gsm_dlci *dlci = tty->driver_data;
3090 if (dlci->state == DLCI_CLOSED)
3092 return dlci->modem_rx;
3095 static int gsmtty_tiocmset(struct tty_struct *tty,
3096 unsigned int set, unsigned int clear)
3098 struct gsm_dlci *dlci = tty->driver_data;
3099 unsigned int modem_tx = dlci->modem_tx;
3101 if (dlci->state == DLCI_CLOSED)
3106 if (modem_tx != dlci->modem_tx) {
3107 dlci->modem_tx = modem_tx;
3108 return gsmtty_modem_update(dlci, 0);
3114 static int gsmtty_ioctl(struct tty_struct *tty,
3115 unsigned int cmd, unsigned long arg)
3117 struct gsm_dlci *dlci = tty->driver_data;
3118 struct gsm_netconfig nc;
3121 if (dlci->state == DLCI_CLOSED)
3124 case GSMIOC_ENABLE_NET:
3125 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3127 nc.if_name[IFNAMSIZ-1] = '\0';
3128 /* return net interface index or error code */
3129 mutex_lock(&dlci->mutex);
3130 index = gsm_create_network(dlci, &nc);
3131 mutex_unlock(&dlci->mutex);
3132 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3135 case GSMIOC_DISABLE_NET:
3136 if (!capable(CAP_NET_ADMIN))
3138 mutex_lock(&dlci->mutex);
3139 gsm_destroy_network(dlci);
3140 mutex_unlock(&dlci->mutex);
3143 return -ENOIOCTLCMD;
3147 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3149 struct gsm_dlci *dlci = tty->driver_data;
3150 if (dlci->state == DLCI_CLOSED)
3152 /* For the moment its fixed. In actual fact the speed information
3153 for the virtual channel can be propogated in both directions by
3154 the RPN control message. This however rapidly gets nasty as we
3155 then have to remap modem signals each way according to whether
3156 our virtual cable is null modem etc .. */
3157 tty_termios_copy_hw(&tty->termios, old);
3160 static void gsmtty_throttle(struct tty_struct *tty)
3162 struct gsm_dlci *dlci = tty->driver_data;
3163 if (dlci->state == DLCI_CLOSED)
3166 dlci->modem_tx &= ~TIOCM_DTR;
3167 dlci->throttled = 1;
3168 /* Send an MSC with DTR cleared */
3169 gsmtty_modem_update(dlci, 0);
3172 static void gsmtty_unthrottle(struct tty_struct *tty)
3174 struct gsm_dlci *dlci = tty->driver_data;
3175 if (dlci->state == DLCI_CLOSED)
3178 dlci->modem_tx |= TIOCM_DTR;
3179 dlci->throttled = 0;
3180 /* Send an MSC with DTR set */
3181 gsmtty_modem_update(dlci, 0);
3184 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3186 struct gsm_dlci *dlci = tty->driver_data;
3187 int encode = 0; /* Off */
3188 if (dlci->state == DLCI_CLOSED)
3191 if (state == -1) /* "On indefinitely" - we can't encode this
3194 else if (state > 0) {
3195 encode = state / 200; /* mS to encoding */
3197 encode = 0x0F; /* Best effort */
3199 return gsmtty_modem_update(dlci, encode);
3202 static void gsmtty_cleanup(struct tty_struct *tty)
3204 struct gsm_dlci *dlci = tty->driver_data;
3205 struct gsm_mux *gsm = dlci->gsm;
3208 dlci_put(gsm->dlci[0]);
3212 /* Virtual ttys for the demux */
3213 static const struct tty_operations gsmtty_ops = {
3214 .install = gsmtty_install,
3215 .open = gsmtty_open,
3216 .close = gsmtty_close,
3217 .write = gsmtty_write,
3218 .write_room = gsmtty_write_room,
3219 .chars_in_buffer = gsmtty_chars_in_buffer,
3220 .flush_buffer = gsmtty_flush_buffer,
3221 .ioctl = gsmtty_ioctl,
3222 .throttle = gsmtty_throttle,
3223 .unthrottle = gsmtty_unthrottle,
3224 .set_termios = gsmtty_set_termios,
3225 .hangup = gsmtty_hangup,
3226 .wait_until_sent = gsmtty_wait_until_sent,
3227 .tiocmget = gsmtty_tiocmget,
3228 .tiocmset = gsmtty_tiocmset,
3229 .break_ctl = gsmtty_break_ctl,
3230 .cleanup = gsmtty_cleanup,
3235 static int __init gsm_init(void)
3237 /* Fill in our line protocol discipline, and register it */
3238 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3240 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3245 gsm_tty_driver = alloc_tty_driver(256);
3246 if (!gsm_tty_driver) {
3247 tty_unregister_ldisc(N_GSM0710);
3248 pr_err("gsm_init: tty allocation failed.\n");
3251 gsm_tty_driver->driver_name = "gsmtty";
3252 gsm_tty_driver->name = "gsmtty";
3253 gsm_tty_driver->major = 0; /* Dynamic */
3254 gsm_tty_driver->minor_start = 0;
3255 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3256 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3257 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3258 | TTY_DRIVER_HARDWARE_BREAK;
3259 gsm_tty_driver->init_termios = tty_std_termios;
3261 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3262 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3264 spin_lock_init(&gsm_mux_lock);
3266 if (tty_register_driver(gsm_tty_driver)) {
3267 put_tty_driver(gsm_tty_driver);
3268 tty_unregister_ldisc(N_GSM0710);
3269 pr_err("gsm_init: tty registration failed.\n");
3272 pr_debug("gsm_init: loaded as %d,%d.\n",
3273 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3277 static void __exit gsm_exit(void)
3279 int status = tty_unregister_ldisc(N_GSM0710);
3281 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3283 tty_unregister_driver(gsm_tty_driver);
3284 put_tty_driver(gsm_tty_driver);
3287 module_init(gsm_init);
3288 module_exit(gsm_exit);
3291 MODULE_LICENSE("GPL");
3292 MODULE_ALIAS_LDISC(N_GSM0710);